Semidried Isada krill (Euphausia pacifica) was treated with boiling water and subcritical water at 100-240C for 10 min with a semidried krill to a water ratio of 8/52 w/v to produce seasoning. The protein concentration, lipid content and odor concentration of the extract increased after increasing the treatment temperature. The highest protein content of the extract (0.047-0.049 kg/kg-extract) was obtained by subcritical water treatment at 180 or 200C. Compounds with lower molecular mass were detected in the extracts derived from subcritical water treatment at temperatures higher than 160C. The extract prepared by subcritical water treatment at 160 and 180C received the high score in the flavor preference test by a group of panelists. Treatment at temperatures lower and higher than 160-180C, respectively, conferred undesirable fishy and smoky or burnt odors to the extracts and residues.
PRACTICAL APPLICATIONAlthough Isada krill is abundant in the Sanriku coast, Japan, its usage is limited to low-value-added products such as animal and aquaculture feeds. However, we found that subcritical water treatment of the krill produces an extract solution and a solid residue, both of which possess good flavor and proffer a great prospective for use as seasoning. Establishment of a method for using the krill as a raw material for seasoning with shrimp-like flavor would increase the value of the krill as a food resource for human consumption.
Effects of the oil-droplet diameter and emulsification with polymerized sodium caseinate (PNC) on the stability of squalene oil (SQ) retention in spray-dried powder were investigated. The SQ droplet diameter significantly affected the stability of the oil in spray-dried powders. The degradation behavior of SQ powders at 105 C was correlated using the Avrami equation. This oxidation mechanism may occur because of the propagative transfer of radical oxidation between oil-droplet particles. SQ emulsified with 5 wt% PNC and small oil droplets had better oxidative stability when compared with 3 wt% sodium caseinate (NC).
Effects of oil fractions and oil-droplet sizes within microcapsules produced by dehydrating oil-inwater (O/W) emulsions on the surface oil content were examined by simulating the two-and threedimensional models of percolation, depicted by square and cubic models, respectively. The square and cubic models were divided into N o ×N o and N o ×N o ×N o equal lattices, respectively, where N o was the number by which a side of the models was divided. A random number ranging from 0 to 1 was generated for each lattice. When the number was smaller than a volumetric oil fraction, the lattice was considered to be occupied by oil. The oil in the lattices connected with the surface lattice on a side or a plane in the two-and three-dimensional models was assumed to be extractable. In both the models, the surface oil content was lower when the oil content was lower in the solid microcapsules, especially when the N o values are larger (smaller oil droplets). The simulation suggested that the smaller droplets were more favorable for the production of microcapsules wherein the oil was hardly oxidized. The effect of the formation of central voids in the microcapsules on the surface oil content was also examined. The formation of larger voids made the content larger, although this effect was not significant.
Pacific krill () contains high amounts of astaxanthin, a carotenoid pigment with strong antioxidative activities. In this study, the effects of subcritical water temperatures (100-180 °C) and times (0-10 min) on color changes (*, *, and*) and astaxanthin degradation in Pacific krill were investigated. In addition, an aqueous solution of pure astaxanthin and that of crude astaxanthin from Pacific krill, both at a concentration of 5 mg/L, were subjected to treatment under subcritical water conditions using a flow-type reactor to compare the degradation of free astaxanthin and astaxanthin fatty acid esters. To compare the results of the different treatment conditions on the properties of astaxanthin, the severity factor (log ) was calculated, which ranged from 0.38 to 3.52. The extractability of astaxanthin enhanced when the subcritical water treatment was carried out at log values of 2.00-2.44. In contrast, astaxanthin underwent 50% degradation at log > 2.44. The changes in the * values correlated well with the astaxanthin content in the treated krill, while the* and * values might relate to the browning components forming owing to Maillard reaction. The results show that free astaxanthin was less stable than crude astaxanthin under subcritical water treatment.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.